This course examines the dynamic intersection of science, technology, and international relations through the lens of science diplomacy, a relatively young field formally defined in the 2010 report, "New Frontiers in Science Diplomacy." Initially structured around three core dimensions, using science to inform policy, supporting science through international cooperation, and leveraging science to foster diplomatic relationships, science diplomacy has undergone significant evolution over the past 15 years. Today, it is increasingly essential to address global challenges, including climate change, pandemics, migration, and technological disruption. It also reflects the growing importance of science as both a tool and a symbol of power in global affairs. The 2025 report Science Diplomacy in an Era of Disruption highlights how the COVID-19 crisis, geopolitical tensions, and the politicization of science have transformed the global scientific landscape. Emerging scientific powers, such as China, regional innovation hubs, and new actors including cities, tech companies, NGOs, and scientific associations, now operate as diplomatic players in their own right. The rise of tech diplomacy, addressing issues such as artificial intelligence, cybersecurity, and platform governance, underscores the urgent need for expertise at the intersection of science, technology, and foreign policy. The first two parts of the course examine the theoretical foundations and historical evolution of science diplomacy. The third part focuses on tech diplomacy, arguably one of the most urgent and impactful subfields today. This course is ideal for students interested in careers in international affairs, science and technology policy, journalism, consulting, academia, or diplomacy. It equips future professionals with the analytical tools and cross-sectoral skills needed to navigate a world where scientific and geopolitical transformations are deeply intertwined.